HS-125-600 Fan

Study Guide

    The 600 fan was more or less the test bed for the later 700 Hawker.  There are still some Viper powered 600's out there, however virtually all of the 700's have the Garrett 731 engine.  The 600 Fan and the 700's are, except for very minor differences, the same.

Max Ramp Taxi  Weight 25,500 lbs
Max Takeoff Weight 25,500 lbs 
Max Landing Weight 22,000 lbs 
Max Zero Fuel Weight  16,300 lbs 

    The above weights are maximum certificated limits.  The actual maximum weights for a particular flight may vary due to the performance limitations.  If the aircraft can not meet the required "Takeoff Field Length" and "WAT" limitations, (engine out climb performance), the maximum takeoff and/or landing weights are reduced such that the requirements are met.  See the performance charts in the AFM for details.

Vmo / Mmo Sea Level to 12,000 ft 
     Reduce 1 kt / 600 ft to 29,800 ft 
With Mod HSA 252648 
With any Fuel in Ventral Tank
320 kts / 0.77 Mach 
288 kts 
           0.78 Mach
280 kts
Va 196 kts
Vfe      15 Deg 
            25 Deg 
            45 Deg
220 kts 
175 kts 
160 kts
Vle / Vlo 220 kts
(Not with flaps when airborne)
Vmo / Mmo
Max Tire Groundspeed 180 kts
Max Alt T.O. & LDG
  9,000 ft 
 -2,000 ft
Max Enroute Altitude 
Max Altitude 15 Flap
41,000 ft
15,000 ft
Min Temp T.O. & LDG 
Max Slush 
Max Water
-40 Deg C
0.75 inch
0.50 inch
Max Temperature 
Min  Temperature
ISA + 35 C 
-75 C
Max Tailwind T.O/ LDG 
Max X-Wind Takeoff 
Max X-Wind Landing
10 kts
35 kts
Max Runway Slope
Max Fuel Imbalance
500 lbs 
Load Factor Limit 
    Flaps Up 
    Flaps Extended 
2.79 G
2.00 G

Engine Limitations
Garrett TFE 731-3R-1H
N1 N2
 907 C
 927 C
  Abv 927 C 
No Limit 
10 Sec 
  5 Sec 
Takeoff (APR)
101,5 %
101.0  %
907 C
 917 C
 927 C 
5 Minutes 
 5 Seconds 
2 Seconds
Takeoff  w/o APR
101.5 %
100.0 %
929 C
939 C
949 C
5 Minutes 
 5 Seconds 
2 Seconds
Max Continuous
101.5 %
100.0 %
No Limit
Max Overspeed
Max Overtemp
103.0 % 
105.0 %
103.0 %
105.0 %
Abv 977
60 Seconds 
  5 Seconds
Reject Engine

    Engines that have the "3 D" mod have the same thrust at sea level, but an increase in thrust at altitude.  The "3 D" engines also burn about 100 pounds per side less fuel per hour.  They make the airplane about 15 knots faster, on less fuel, therefore increasing the range.  For example, a 600 fan would barely make Las Vegas from Ft. Lauderdale, until the 3 D mod was done.  Then Ft. Lauderdale to Long Beach was done, landing with more fuel than we previously had when we landed in Vegas.  The mod really does make a difference.

 Engine Oil System Limitations
Max Oil Temp  to 30,000 ft 
                  above 30,000 ft
127 C 
140 C
Max Transient Oil Temp
149 C
Min Oil Temp for Start 
Min Oil Temp Above Idle
-40 C
+30 C
Max oil consumption / 25 Hours 
1 Quart 


Flight Controls

     The ailerons and elevator and rudder on the HS-125/700 are manually actuated by the pilots.  The aircraft does have an autopilot.  The ailerons and elevator may be moved by the autopilot servos, and the rudder is equipped with a yaw damper, and a rudder bias system.

Rudder Bias
     The rudder bias system uses engine bleed air to reduce the required rudder force during flight with one engine failed, or producing substantially less thrust than another.  Bleed air from the right engine applies right rudder, and bleed air from the left engine applies left rudder.  When both engines are operating, the net result is zero.  When one engine fails, the bleed air from the operating engine applies a force moving the rudder toward the operating engine.  The Jetstar and King Air have similar systems.  These type systems are about as reliable as an iron ball.  Not much to go wrong here!

    The flap system is hydraulic.  The flaps may be extended or retracted by the main or emergency hydraulic systems.   The flaps are also a component of the "Lift Dump" system.  Do not extend flaps when airbrake is extended.  When aircraft is parked for some time, the flaps may extend due to loss of hydraulic pressure.  This is normal.  They will return to their selected position when the hydraulic system is pressurized.

     The airbrake system consists of panels located on the upper surface of each wing.  They are hydraulically actuated by a single "Airbrake / Lift Dump" handle in the cockpit.  The airbrake must be in the retracted position whenever flaps are extended.  The only exception to this is during the landing roll.  Lift dump can not be selected unless flaps are in the landing position.

Lift Dump
     The Lift Dump system consists of the flaps, and the airbrake.  Lift Dump may be selected only when the flaps are in the fully extended position.  After landing, apply the airbrake.  When it reaches the aft stop, pull the lever slightly up, and then aft and down.  This extends the flaps to a nearly vertical position, and substantially increases drag.  You will be surprised at how effective they are.  Do not attempt to retract the flaps until the airbrake handle has been placed to the stowed position.  If lift dump is desired on a rejected takeoff, the flaps must be selected to and reach the 45 degree position prior to lift dump deployment.

Nosewheel Steering
     The nosewheel steering system is hydraulic, and works with pressure from the main system.  During landing gear extension and retraction, the tiller must be free to rotate, unobstructed by anything placed on the side panel.  Failure to comply with this requirement may cause the tower to see both sides of the aircraft on the landing roll.  If the main system pressure is lost, the nosewheel steering will be inop.  To cope with this, you have two options once you have lost rudder effectiveness, let the airplane go where it wants, or use differential braking.  The second option is the wiser one.   The emergency  braking system will allow this.
    Do not forget to correctly install the nosewheel steering pin.  Vertical is the position for taxi, and horizontal will disengage the steering mechanism, and allow the attachment of a towbar.  Sometimes ground personnel may attempt to "help" and improperly install this pin.  Check it yourself.  That's why you make the "big bucks".

     The normal braking system provides braking to all of the main gear wheels.   Anti skid protection is provided by mechanical devices located in the axles.  Emergency brakes and parking brake is provided by an accumulator that is charged by the main system.  With the brake control lever full forward, the normal brakes function as dictated by the pressure on the brake pedals.  With the brake control lever in the center, or first detent, the emergency brakes work, again, as dictated by the brake pedals.  Anti-Skid is not available when emergency brakes are in use.  Pull the lever full aft, and the parking brake is engaged.  If this is done with the aircraft in motion, the tires won't like you much.  Neither will the passengers for that matter.  If the brake accumulator is discharged, pump the pressure up with the handle in the tailcone.  This may prevent some excitement when the engines are started.

Fuel System

     The HS-125/700 carries it's fuel in the wings, and in a ventral tank.  The fuel is supplied to the engine driven fuel pumps by an electric boost pump located in each wing tank.  Two valves are installed between the respective sides of the fuel system.  The "Crossfeed " valve allows feeding of one engine from the opposite tank, and feeding both engines from a single tank.  The "Interconnect" valve allows fuel transfer between the two wing tanks.
     To "Crossfeed", place the fuel Crossfeed / Transfer lever to the first detent.  This opens the crossfeed valve.  Leave the boost pump ON in the tank you wish to feed from.  Turn the opposite boost pump off.  The operating boost pump provides fuel to any engines that are running.
 To "Transfer" fuel, place the fuel Crossfeed / Transfer lever to the "Interconnect" position.  This opens both the crossfeed and transfer valves.  Leave the boost pump on in the tank you wish to transfer TO!  Turn off the pump on the side from which you wish to extract the fuel.  Remember, always open the valves prior to turning off any pumps, and turn on all pumps before closing any valves.

Fuel Management Restrictions

No Fuel may be placed in the Ventral tank unless wings have 3,600 lb per tank.
Ventral tank must be Full, or empty, no partial fuel load for this tank.
Ventral tank fuel must be transferred to wings when each wing reaches 3,300 lbs.
Max 280 kts with fuel in Ventral tank.
Landing with fuel in ventral tank prohibited except in emergency.
Dorsal tank must be full or empty for takeoff.  No fuel in dorsal without full ventral tank.
8,160 lbs
   872 lbs
   408 lbs
9,440 lbs

Hydraulic System

     The main hydraulic system on the HS-125/700 uses 5606 fluid.  System pressure is 3,000 psi, accumulator precharge is 1,000 psi, and the reservoir capacity is 2.4 gallons.  Pressure regulated engine bleed air pressurizes the hydraulic reservoir to a between 10 and 18 psi.  It operates the landing gear, brakes, flaps, airbrakes, lift dump, and nosewheel steering systems. There is an emergency system that may be used to lower the landing gear, and operate the wing flap system.

     The main hydraulic system has an engine driven pump driven from the accessory drive shaft (N2), on the each engine, and a hydraulic reservoir in the tailcone.  There are annunciator lights in the cockpit that tell you if each hydraulic pump is operating.  A hand pump in the tailcone allows operation of all main hydraulic devices without  any other source of hydraulic pressure.   The main system is used to charge the brake accumulator to provide a parking brake, and emergency braking if the main hydraulic system fails, or is just not operating, such as on the ground prior to engine start.  This system may be charged by a hand pump located in the tail of the airplane.  This is not to be confused with the "Emergency " system.  The hand pump in the tail provides pressure to the main system, but at a lower rate than the engine driven pumps, unless you are Charles Atlas on steroids!  The hand pump in the cockpit operates the emergency system only.

     The emergency hydraulic system will lower the landing gear, and operate the wing flaps.  To activate the system, place the gear switch down, pull the emergency gear extension handle on the left side of the throttle quadrant, and pump.  The gear will come down slowly, as you operate the hand pump.  To operate the flaps, merely select the flap position you desire, and operate the hand pump until the flaps reach that position.  The flaps may be extended or retracted, however the landing gear may only be Extended with the emergency system.  The emergency system reservoir holds 6 pints of fluid, and is located in the nosewheel well.  It is depleted when the emergency system is used, so if you pump the flaps to check the system, have maintenance check and possibly service the emergency reservoir.

Electrical System

    The HS-125/700 is equipped with two starter generators, two main batteries, and one or two additional  batteries.  The main batteries provide power for starting the engines, and emergency power in the event both generators are lost.  The loss of one generator will not cause loss of any equipment, as the "Bus Tie" relay will allow one generator to power the entire DC electrical system. The amber Bus Tie light will illuminate if the bus tie is open.  If this is the case, the PE bus will be powered, but the respective PS busses are powered only if their generator is operating.  The number 3 battery powers:  Emergency horizon, and the lighting for the standby altimeter and standby airspeed indicator.
    The AC system consist of three inverters, 1, 2, and standby.  The # 1 and # 2 inverters power the main and essential AC busses.  Failure of one of the main inverters does not result in loss of equipment.  Failure of both inverters will cause the standby inverter, if armed, to power the Captains instruments.  The standby inverter is powered by the "PE" bus, and the # 1 and # 2 inverters are powered by PS 1 and PS 2 respectively.
Voltage 28  Volt
Generators 300 Amps 
APU / Garrett 
         / Solar 
250 Amps 
300 Amps @ ISA + 23 C 
265 Amps above
Batteries 1 & 2 
Battery       3 
24 Volt / 23 Amp Hour 
24 Volt / 04 Amp Hour

Ice Protection

        The Hawker 700 is equipped and certificated for flight into known of forecast icing conditions.  The engine nacelles and stator vanes are anti-iced with hot high pressure bleed air.  The pitot tubes and static ports are heated with DC electrical power.  The windshields are heated with variable frequency AC power from alternators on each engine.  If both alternators are operating, each alternator powers it's respective window.  If only one alternator is operating, both front windshields will be heated by the operating alternator. Windshield heat is to be turned on prior to takeoff, and left on for the duration of the flight.  If the window heat trips off in-flight, do not reset unless the indicated outside air temp is warmer than -30 C.  The wings and tail are anti-iced by pumping an anti-icing fluid through tiny holes in the leading edges of the wings and tail.  Prior to entering icing conditions, turn on the TKS to distribute the fluid.  Prime the TKS system by running the pump for 3 minutes prior to takeoff.   This system is a "pain in the ass" when it leaks fluid onto the hangar floor, but works well in flight.
    The Hawkers are equipped with an Ice Detector.  The ice detector is powered through the left squat switch.  It consists of a motor driven serrated rod extending from the side of the nose of the aircraft.  Within a few thousands of an inch aft of this rod is a triangular "cutter".  When ice forms on the rod, it jams between the rod and the cutter, increasing the torque on the electric motor. When the torque exceeds a predetermined value, the ice detection light in the cockpit.


     The Hawker 700 is heated, cooled, and pressurized by engine bleed air.  Bleed air is extracted from both engines.   The air travels through the "Refrigeration Unit" or air cycle machine.  This consists of a heat exchanger, a compressor, another heat exchanger, an expansion turbine. A temperature control valve may be opened or closed to regulate the amount of air that goes through the ACM, and the amount that goes around it.  Since the bleed air is hot, and it was not cooled by going through the air cycle machine, the cabin temp will increase.
    The cabin temperature control valve is positioned electrically.   Both manual, and automatic temp control require electrical power.  Manual allows the "Cold / Hot" switch to move the valve to the desired position.  "Auto" on a Hawker  positions the temperature control valve in accordance with instructions from a thermostat.  I suggest you use manual temp control.  There is a "Flight Deck Heat" switch in the cockpit.  When opened, it supplies warm bleed air to the flight deck independent of the refrigeration unit.  This air comes from the right engine.
    Three switches control the flow of air into the pressurized compartment on the airplane.  The flight deck heat switch, and the two "Air Valves", or engine bleed air switches.  The "Air Valve" switches have three positions, Off, HP, and LP.  LP is used normally only at cruise, or when N1 rpm is to remain high.  HP is a must on descent as LP will not provide enough air to pressurize the airplane in most cases.  The air valves are to be turned on as soon as airborne, and off just prior to landing.
    In the case of air conditioning smoke, the bleed air sources may be turned off one at a time to diagnose the problem, or all at once, if the smoke is severe enough.  If the source of the smoke is the engines, you may isolate the offending air source.  If the smoke is being generated by the refrigeration unit, you can pressurize with the flight deck heat until landing.  It will be a little hot, but you can still breathe.
Flight Profiles

    Here are some basic flight profiles that I have used over the years.  They are not the only way to fly the airplane, but have worked for me since I started giving training and checkrides a little over 20 years ago.  In the event of a difference between this and the Aircraft Flight Manual, the flight manual is the document to follow.

Steep Turns

1.  Enter at 250 KTS indicated AIRSPEED.
2.  Bank aircraft 45 deg.  As you pass 30 deg of bank, pitch up 2 deg.  Add power to maintain AIRSPEED.
3.  Lead roll out by 15 deg.  Passing 30 deg bank, pitch down 2 deg  to maintain  altitude.
4.  Maintain 250 KTS and assigned heading.

Stall - Cruise Configuration

1.    Compute Vref & set AIRSPEED bugs.
2.    Maintain assigned altitude and set power to 50% N1.
3.    Trim for level flight until passing 150 KTS.  Maintain altitude with necessary back pressure.
4.    At stick shaker,  throttles to " MAX POWER "
5.    Call " MAX  POWER Flaps 15 deg.
6     Reduce pitch ONLY to the extent necessary to eliminate symptoms of the stall.
7.    Reestablish assigned altitude.
8.    At Vref + 20 KTS, call " Flaps Up, After Takeoff Checklist.  "
9.    Maintain AIRSPEED and altitude as directed.

Stall - Takeoff Configuration

1.  Compute Vref, set AIRSPEED bugs & select flaps 15 deg.
2.  Maintain assigned altitude and set power to 50% N1.
3.  Trim for level flight until passing 150 KTS.
4.  Maintain altitude and establish 25 deg bank angle.
5.  At stick shaker or stall lights, advance throttles & call " MAX POWER ".
6.  Level wings & reduce pitch ONLY to the extent necessary to eliminate symptoms of the stall.
7.  Reestablish assigned altitude.
8.  At Vref + 20 KTS, call " Flaps Up, After Takeoff Checklist.  "
9.  Maintain AIRSPEED and altitude as directed.

Stall - Landing Configuration

1.    Slow to flap speed, set 60% N1 & Set bug to Vref.
2.    Maintain assigned heading & altitude.
3.    Below 220 KTS, " Flaps 15 deg".
4.    Below 220 KTS, " Gear Down Landing Check ".
5.    Below 175 KTS, " Flaps 25 deg".
6,    Below 160 KTS,  "Flaps - Landing"
7.    Below 150 KTS, " Full flaps. " trim to Vref. Establish a 400-700 feet/min sink rate at Vref.
8.    Level off at designated altitude  W I T H O U T  increase in power
9.    Maintain altitude until  first indication of a stall. (Shaker or aerodynamic buffet)
10.  Apply MAX power , call for "Flaps 25 deg, lower nose as required to eliminate the stall warning.
       At Vref minus 10 KTS   M I N I M U M  speed, call for " Flaps 15 deg", and increase the
       pitch attitude to 10 deg nose up at about 1 deg / sec.
10.  When VSI & Altimeter indicate positive rate of climb call " Positive rate, Gear Up ".
11.  Establish 7.5 deg nose up attitude.
12.  At Vref + 20 KTS, Call " Flaps Up, After Takeoff Checklist ".
13.  Return to entry heading and altitude or as directed.

ILS Approach - Two Engines

1.    Intercept LOC at 140-160 KTS and Flaps 15 deg.
2.    One dot prior to intercepting Glide Slope, call " Gear Down Landing Check ".
3.    When ON the glidepath, call " Full Flaps ".
4.    Establish Vref to Vref + 5 KTS & track LOC & GS until Minimums.

ILS Approach - One Engine

1.  Intercept LOC at 140-160 KTS and Flaps 15 deg.
2.  One dot prior to intercepting Glide Slope, call " Gear Down Landing Check ".
5.  When ON the glidepath, call "Flaps 25 deg".
6.  Establish Vref + 15 KTS & track LOC & GS
7.  At 50 Ft AGL, Full flaps if desired, power as necessary & land.
7. After touchdown, Verify Full Flaps
9.  Lift Dump - Extend

Non Precision Approach - One or Two Engines

1.    Intercept Final Approach Course at 140 KTS and Flaps 15 deg.
2.    Crossing Final Approach Fix, call " Gear Down Landing Check ".
3.    Descend to and maintain MDA until Field in Sight or MAP is initiated. ( As Appropriate ).
4.    If Landing is to be made, call " Full Flaps " when intercepting a glidepath appropriate for a
       normal landing.  For one engine INOP, Vref + 15 KTS until 50 feet AGL, then " Full
       Flaps" so as to perform a normal landing.

No Flap Approach

1.  Vref + 20 KTS until established on Final Approach.
2.  Vref + 15 KTS on final.
3.  Approach angle NORMAL.  A flat approach will usually result in a longer landing roll.

Go Around or Missed Approach

1.  "Max Power", Rotate to 10 deg pitch up, " Flaps 15 deg".
2.  Positive Rate of Climb, " Gear Up ", Vref + 20, " Flaps up, After Takeoff Checklist ".
3.  Climb at 200 KTS.
4.  Engine Failure or Fire Checklist if Appropriate.


1.  Set V2 on Capt. Airspeed & V1 on Co-Pilots Airspeed.
2.  At 80 kts, left hand moves from tiller to Yoke.
3.  At V1, right hand moves from throttles to Yoke.
4.  Vr, Rotate to 15 deg ( 2 eng ) 12 deg ( 1 eng ).
5.  Climb at 15 deg pitch, ( 2 eng ) or V 2 ( 1 eng ).
6.  At 400 ft & V2+20 KTS, "Flaps Up After T.O. Check ".
7.  Engine Failure or Fire Checklist if Appropriate.
8.  Climb  200 KTS to 3000 AGL then 250 Kts.

Rejected Takeoff

1.  Proceed as in normal takeoff until malfunction dictates that the takeoff be rejected.
2.  Capt. calls "Abort" (Co-Pilot may call Abort if Capt elects to delegate that authority).
3.  Thrust levers to idle
4.  Speedbrakes extend.
5.  Landing Flaps
6.  Lift Dump - Deploy
7.  Wheel brakes as necessary.
8.  Thrust Reverse OR Dragchute deploy.  (Never Both!)
9.  If another takeoff is contemplated consider brake energy & appropriate turnaround time.

Note:  I do not recomend that you initiate a practice aborted takeoff at more than 40 knots, as it adds nothing to the value of the training, and may cause damage to the brakes and tires if performed imperoperly.

Emergency Descent

 1.    Oxygen masks on within 5 sec of cabin pressure loss.
 2.    Check passenger oxygen masks deployed.
 3.     Select Oxygen mask microphone.
 4.    Ignition ON.
 5.    Thrust levers to idle.
 6.    Extend Speedbrakes
 7.    Initiate 45 deg bank if desired.
 8.    Vmo/Mmo minus 10 kts to 14,000 or MEA as required.
 9.  Clean up & proceed to nearest suitable airport if appropriate.  Condition of aircraft or
                      reduced range due to low altitude may make flight to original destination unwise.

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